Use testtools instead of unittest or unittest2.

As part of the move towards testr and parallel test running, we
start to use testtools and fixtures to make the test suite
resilient and more pedantic.

Part of blueprint grizzly-testtools

Change-Id: I90250de9fe21237db34f6a50b89b15863e270aa5
Make sure all db accesses use subtransaction

Fixes bug 1133253

Change-Id: If952eaa919cdc7536023525a397e7a8ce4b425aa
Fetch all pages when listing NVP Nat Rules

Bug 1133318

Change-Id: I24e9943b4771c4f2b941c229ba1c300dfbf7e331
Limit amount of fixed ips per port

Fixes bug 1100476

The patch also updates the quantum configuration file to
contain the following:
 - max number of host routes
 - max number of dns servers

Change-Id: Ic5d90034b0231687dfbde8fc65780ab52222c0fd
Fix NVP plugin not notifying metadata access network to DHCP agent

Bug 1133395

Due to recent changes in notification logic between Quantum and the DHCP
agent, the notifier the NVP plugin previously used for metadata access
network was not working anymore and needed to be replaced

Change-Id: Ifa0ea55116cf5ef6d546d28ca52e643987b3e5a0
Remove network type validation from provider networks extension

Bug 1133064

As the set of valid network types for the provider networks extension
depends on the particular plugin, validation should be performed there.

Change-Id: I3ce5762458bc553625a458ace80072bd804e31f0
Imported Translations from Transifex

Change-Id: Ic0f16a8108abb85b50355b837ae889b22c703886
Merge "Fix NVP plugin not notifying metadata access network to DHCP agent"
Merge "Fetch all pages when listing NVP Nat Rules"
Enable multiple L3 GW services on NVP plugin

Bug 1130211

This patch allows for using multiple layer-3 gateways leveraging the
provider networks extension.

Change-Id: I293920c2565f4670e9be9b22dc1b60431b62f7e7
Merge "Imported Translations from Transifex"
Merge "Limit amount of fixed ips per port"